For those interested I have some Hilux calipers that needed fixing, one was siezed another was completely blocked. The siezed one was a simple matter of pulling the pistons out cleaning them up, greasing up and putting back together, the blocked one had to be completely dismantled. Below is a video that helped, some vids showed using compressed air to get the pistons out but the seized ones wouldnt budge so had to be pulled out with vice grips. Also here is a pic of what is left when you completely dismantled one, I imagine a Sierra one will be similar but with only one big piston.
